HR: 1330h
AN: A13A-17    [Abstracts]
TI: Analysis of Halogens in Antarctic Snow and Their Role in Boundary Layer Ozone Depletion Events.
AU: * Kalnajs, L
EM: kalnajs@colorado.edu
AF: University of Colorado / Laboratory of Atmospheric and Space Physics, 1234 Innovation Dr., Boulder, CO 80303 United States
AU: Davis, S
EM: seand@colorado.edu
AF: University of Colorado / Laboratory of Atmospheric and Space Physics, 1234 Innovation Dr., Boulder, CO 80303 United States
AU: Avallone, L
EM: avallone@lasp.colorado.edu
AF: University of Colorado / Laboratory of Atmospheric and Space Physics, 1234 Innovation Dr., Boulder, CO 80303 United States
AB: It is generally accepted that tropospheric ozone depletion events in polar regions involve halogen chemistry, in particular bromine chemistry. It has also been suggested that snow has an important role in the destruction of tropospheric ozone. Blowing snow and the surface layer of the snow pack provide a large surface area for heterogeneous chemical reactions as well as being a possible source or sink for gas phase atmospheric Bromine. In the austral spring of 2004 we collected and analyzed snow samples from the Ross Island region in Antarctica to determine snow's role as a source of atmospheric bromine. Seventy snow samples were collected on the Ross Ice Shelf and in various locations on the annual and multi-year sea ice. Various types of snow were analyzed, including freshly fallen snow, wind-blown snow, and aged drifted snow. In this presentation we will describe the sampling process and locations and will discuss the results in the context of snow type and age. The samples were returned to the laboratory for analysis for anions, including bromide and chloride, through ion exchange chromatography. Analysis of the bromide-to-chloride ratio shows that bromide is significantly enhanced in wind-blown snow samples over the values expected purely from sea salt deposition. Significant variation in bromide levels was also observed as a function of geographic location and the age of the snow. In addition to collection of natural snow samples, an experiment was conducted to determine the effect of solar radiation on bromine levels on snow artificially seeded with bromide.
DE: 0322 Constituent sources and sinks
DE: 1863 Snow and ice (1827)
DE: 3307 Boundary layer processes
DE: 9310 Antarctica
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly